Animal Diversity Web

Geographic Range

Saimiri oerstedii inhabits parts of the Pacific coast of Panama and Costa Rica (Nowak, 1999).

• Biogeographic Regions
• neotropical
  • native

Habitat

Little information is available about the habitat of S. oerstedii. In general, squirrel monkeys are arboreal and can be found in primary and secondary forests (Nowak, 1999), thickets, and mangrove swamps (Macdonald, 1984). They are also found in cultivated areas, usually around streams (Nowak, 1999). Saimiri oerstedii is known to inhabit humid Pacific slope forests (Reid, 1997).

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• forest
• rainforest

Physical Description

Saimiri oerstedii is a small, slender monkey with a long tail (Reid, 1997). Much of their body fur is yellow brown in color with a pale yellow belly (Reid, 1997). Saimiri oerstedii can be distinguished from its sister species Saimiri sciureus because the crown of S. oerstedii is covered with black fur while that of S. sciureus is not (Chiarelli, 1972). Also, S. oerstedii has golden-red colored fur on its back (Rosenblum and Coe, 1985). Saimiri oerstedii weighs between 500 and 1100 g (Reid, 1997). Squirrel monkeys are typically 225 to 295 mm long with tails adding between 370 and 465 mm (Chiarelli, 1972).

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  500 to 1100 g

  17.62 to 38.77 oz

• Range length

  225 to 295 mm

  8.86 to 11.61 in

Reproduction

The birth rate in the genus Saimiri is about one birth per year (no information specifically for S. oerstedii). Females do not resume cycling until their infant either dies or is weaned (Smuts et al., 1987). The infants are usually born at night (Parker, 1990). Females of S. oerstedii give birth to one young after a gestation period of 7 months (Reid, 1997). The births usually occur during the wet season (Reid, 1997). Although no data were available S. oerstedii, females of its sister species Saimiri sciureus are in a period of estrous around 12 to 36 hours (Hayssen et al., 1993)

Females are sexually mature at about 1 year old, males reach sexual maturity between 4 and 6 years old.

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
• viviparous

• Breeding interval

  The birth rate in the genus Saimiri is about one birth per year

• Average number of offspring

  1

• Average number of offspring

  1

  AnAge

• Average gestation period

  7 months

• Average age at sexual or reproductive maturity (female)

  1 years

• Average age at sexual or reproductive maturity (male)

  4-6 years

In general, a Saimiri mother takes care of the young although sometimes other females help (Parker, 1990). These females are sometimes referred to as "aunts" (Parker, 1990).

For the first few weeks of its life, an infant of genus Saimiri, probably including S. oerstedii, rides along on its mother's back and nurses, with little attention paid to it by the group members (Parker, 1990). During its third and fourth weeks of life, the young monkey begins to move around more and between weeks five and ten, it occasionally disembarks from its mother's back, explores the nearby area, and starts to eat solid foods (Parker, 1990). Over the next couple of months, contacts with the mother become less frequent (Parker, 1990).

In other Saimiri (S. oerstedii is poorly studied), social play first occurs around two months (Parker, 1990). Social play serves to help separate the infant from its mother (Macdonald, 1984). In the first year of life, the young monkeys engage in social play with each other, usually in the form of fighting games (Parker, 1990). Females become adult around month twelve to thirteen while males achieve maturation around their fourth or sixth year (Parker, 1990).

• Parental Investment
• altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • protecting
    • female
• extended period of juvenile learning

Behavior

Saimiri oerstedii is a social species. These monkeys travel in small troops (Baldwin and Baldwin, 1972). A troop of S. oerstedii has been observed to travel between 2.5 and 4.2 km a day with a home range around 0.175 square km (Baldwin and Baldwin, 1972). They begin foraging shortly before sunrise and continue until an hour or hour and a half after sunset, stopping only for brief rests or rainstorms (Baldwin and Baldwin, 1972). They huddle to minimize their exposure to the rain (Baldwin and Baldwin, 1972).

• Key Behaviors
• arboreal
• diurnal
• crepuscular
• motile
• sedentary
• social
• dominance hierarchies

Communication and Perception

• Perception Channels
• tactile
• chemical

Food Habits

The diet of S. oerstedii consists mostly of invertebrates, small vertebrates, fruit, and flower nectar (Reid 1997). They also recognize the leaf-tents made by some fruit-eating bats and attack these tents to extract the bats (Reid 1997).

In general, members of the genus Saimiri feed primarily on fruit, berries, seeds, gums, leaves, buds, insects, arachnids and small vertebrates (Nowak, 1999). Nearly half of their diet is made up of fruit (Smuts et al., 1987). Most of their prey are immobile invertebrates (Smuts et al., 1987). When the animals find food in a tree, they often do not completely use up the resources available and may return to it in the future (Parker, 1990).

• Primary Diet
• omnivore

• Animal Foods
• insects
• terrestrial non-insect arthropods

• Plant Foods
• leaves
• seeds, grains, and nuts
• fruit
• nectar
• sap or other plant fluids

Economic Importance for Humans: Positive

Squirrel monkeys in general (not specifically S. oerstedii) do benefit humans in that they are very widely used in biomedical research (Strier, 2000). Half of all squirrel monkeys imported to the United States in 1968 were used in labs while the other half were used in zoos and the pet trade (Nowak, 1999). They are often used for aerospace research as well (Rosenblum and Cooper, 1968). In the past, they have also been kept as pets for the European and American aristocracy (Hearn, 1983).

• Positive Impacts
• pet trade
• research and education

Conservation Status

Although its sister species, S. sciureus, is quite abundant the IUCN places S. oerstedii on the endangered list (Nowak, 1999). The population has declined drastically with the destruction of forest habitats (Nowak, 1999). While abundant in the regions it inhabits, S. oerstedii is restricted to a very small area ( Smuts et al., 1987).

• IUCN Red List

  Vulnerable
  More information

• IUCN Red List

  Vulnerable
  More information

• CITES

  Appendix I

Other Comments

There have been some difficulties in finding information on S. oerstedii due to its rarity. In general, it is believed to be very similar to its sister species, S. sciureus (Moynihan, 1976). Also, the taxonomy of the genus is not completely resolved. Some authors divide Saimiri into two species, S. sciureus and S. oerstedii (Parker, 1990) while others see between five species (Nowak, 1999) and only one species which can be divided into two subspecies (Moynihan 1976).

Contributors

Thomas Ambrose (author), University of Michigan-Ann Arbor, Ondrej Podlaha (editor), University of Michigan-Ann Arbor.

References

Baldwin, J., J. Baldwin. 1972. THe ecology and behavior of squirrel monkeys( *Saimiri oerstedii*) in a Natural Forest in Western Panama. Folia Primatologica, 18: 161-184.

Chiarelli, A. 1972. Taxonomic Atlas of Living Primates. London: Academic Press.

Hayssen, V., A. Van Tienhoven, A. Van Tienhoven. 1993. Asdell's Pattern of Mammalian Reproduction. Ithaca: Cornell University Press.

Hearn, J. 1983. Reproduction in New World Primates. Lancaster: MTP Press Limited.

Macdonald, D. 1984. the Encyclopedia of Mammals. New York: Facts on File, Inc..

Moynihan, M. 1976. The New World Primates. 1976: Princeton University Press.

Nowak, R. 1999. Walker's Mammals of the World. Baltimore and London: The John's Hopkins University Press.

Parker, S. 1990. Grzimek's Encyclopedia of Mammals. Munchen: McGraw-Hill, Inc..

Reid, F. 1997. A Field Guide to the Mammals of Central America and Southeast Mexico. Oxford: Oxford University Press.

Rosenblum, L., C. Coe. 1985. Handbook of Squirrel Monkey Research. New York: Plenum Press.

Smuts, B., D. Cheney, R. Seyfarth, R. Wrangham, T. Struhsaker. 1987. Primate Societies. Chicago and London: The University of Chicago Press.

Strier, K. 2000. Primate Behavioral Ecology. Needham Heights: Allyn and Bacon.